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Chilling and Fermenting

Hi all,

I have been using 55 gallon poly drums for fermenting for a year and we are expanding pretty soon.

We are upgrading to a 300 gallon mashtun/stripping still and would like to upgrade our fermenters to 300 gallons as well.

I have 2 questions:

  1. Is chilling a 300 gallon open top fermenter necessary?
  2. Does anyone have any experience with using larger poly containers with fermenting as they are much cheaper, or should i go with SS We currently make whiskey, vodka and rum?

Thank you,



  • Jonny VerPlanck reckons anything up to about 250-300 gallons is fine with no climate control. I said fine. Not optimal.

    The open top should help to displace some heat.

    StillDragon North America - Your StillDragon® Distributor for North America

  • Here is a thread where I showed doing a 300gal rum wash cooling using recirculation, the recirculation also sped up fermentation and kept temperatures a little more uniform instead of cooking the top:

    Cooling / Heating Fermenter

    I have since gone to 3x 10bbl SS beer conicals, but the process is identical.

  • Couple of notes that may add to your knowledge base.

    I did a bunch of fermenting (5 years) at tropical temperatures (84-93f ambient temps) in open top poly barrels making neutral. The open top will eventually become a limiting factor to producing and MANAGING ferment schedules in a production environment. They need to be distilled quickly after yeast activity drops or stops to prevent bacteria from “adjusting flavor”. Just my opinion but air locks are your friend in most cases.

    I also struggled with controlling temperatures of the ferment. Depending on the yeast used you will discover that rising above a certain temperature (even for a short time) will ruin flavor. For example ec-1118 is no good above about 25c, lallemand SR is no good above 29c and Ab mauri pinnacle is no good above 39c or below 29. I’ve come to the conclusion that temperature controlled fermentation environments are pretty darn important for fermentation. I’ve tried fans and fermentation speed control with varying success but I’m now a proponent of a water jacket and occasional agitation.

  • edited January 20

    Easy to make great whiskey once, really hard to make great whiskey twice.

    Achieving batch to batch consistency of exceptional product is very, very challenging, because it involves following exactly the same steps, over and over in exactly the same way, limiting any potential variation possible (and praying the impossible doesn't vary too much - grain, wood, etc).

    We've found fermentation temperature to be incredibly important in batch to batch consistency. Never did we say, wow that day the chillers failed and the ferments all got hot, that made some really exceptional whiskey. Instead it was, wow, so headsy, so tailsy, distill it as high as possible, cut it as narrow as necessary, and lets hope it is good enough for blending stock.

    Make no mistake, fermenting too cool is not ideal either, but uncontrolled fermentation will generally mean hot fermentation. Hot fermentation will mean more heads, more tails, more off-flavor, lower product yield. Uncontrolled fermentation will mean highly variable flavor profiles.

    Rum is a bit more forgiving of temperature, you could argue that it's part of the characteristic style, however the same rules still apply, especially when you've got fast and furious ferments.

    This is even more important if you are going to attempt to sell young aged product. 6-8 years in a barrel will forgive some of those sins, 1-2 years will not.

  • There are some guys around here who make beer in the 1000l IBC totes and for temperature control they use full depth cooling torpedos hooked up to an immersion sensor. I am planning on doing the same. Great feedback on temperature control. I found doing on grains it was very hard to get consistent temperature control as often the grain cap would act as an insulator, trap in the heat and cook the yeast when the temp hits over 40c. I had my tank mate, fabricated some helical immersion coils and they work very well. I plan to use those with IBC totes when I get my shed built. I am using Safspirit whiskey yeasts now doing off grain ferments as that yeast is a lot better with higher temperatures. I completely agree with Fijispirits on EC1118. Great yeast below 30c. Very variable over 30c.

  • I just hate cleaning the 1000L totes, particularly dried chunks of krausen since they do not drain well... eventually your time and the wear on your body adds up to the cost of a used jacketed beer fermenter...

  • Well I have my tank guy preparing a price for a stainless steel washback with a cooling Jacket with a simple design. If I get my next 4 month contract I will go stainless all the way. Thanks for the tip on the tote. As for cleaning I was thinking of utilising child slave labor but my kids arent that motivated. Maybe a whip would be a good piece of motivational equipment to have in my distillery.

  • Can't hurt.


    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • @donmateo i totally get the immersion coolers. I’ve not worked with them or even seen the different designs. That idea is why I think they put agitator motors on the large fermenters with jackets. I would think the added benefit of moving settling yeast and nutrients around would be a nice benefit. I wouldn’t leave them on all the time but a scheduled cycle based on temps or minimum agitation time would be cool.

    Man, I wanna PID/PLC/temp probe/flow meter everything and send all that shit to my iPad and play that distillery like a game SOO BAD...

    Also I’ll note that an agitator would have the benefit over pump mixing of not releasing a suprise amount of CO2 and making a mess. I admit to never having done this to four open top fermenters in a row and creating floor wash compound and having to use a giant wet dry vacuum to clean it up because we didn’t have floor drains. Yep. Never happened.

  • My knowledge of fermentation is that you leave the tank alone till end without agitation

  • @richard said: My knowledge of fermentation is that you leave the tank alone till end without agitation

    You have to be careful with it. Certainly during the lag/growth phase you don’t want to agitate, but once it gets going I think it doesn’t hurt.

    At least that’s my take on raw sugar washes. I’m not sure how it would effect on-grain.

  • edited January 21

    @fijispirits. I know its uncool to put products up here that are not SD but this is homemade solution, sort of. Here is the cooling cool. It was made to put into an IBC tote but goes very nicely into my 220l fermenting tanks. I am using cooling water from my pool going through one of these. When the water is 10deg it will take a wash from 65 deg C down to 25C in about an hour, when the pool water is about 25C it takes about 2 hours. During summer when I was doing on grains I would leave one of these things in the ongrain for two days and keep recirculating just until most of the heat from the first two days of fermenting was done and then I would take it out. Its made out of SS tubing which is not that great a heat conductor but it works. The vertical bars are solid bars just to keep the coils in the right helical position. For an IBC tote I was planning on having two of them, or even with a stainless steel washback. These things came about after an evening of drinking whiskey. The good thing is they are stainless and I can drop them in a tank of oxidial sterliser and in about 24 hours later then come out cleaner than a virgins conscious. I cant make jokes like that around Andres my tank making mate as his sister is a nun. The only bad things about using these is the cool to depth in the tank and as hot liquids are at the top of a mass of liquid there can be as much as a 3 to 4 degree temperature difference from the temperatures at the top to that at the bottom. I tried fans on my tanks here when it was 38 C and that didnt work, these coiling coils, while rudimentary actually work. Hooked up to a small temperature controlled cooling pump and a wireless setup they could be controlled from your phone. Thats on my list of things to do when my shed finally gets built.


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  • I have one of these that a neighbor brewery lent me, it is a HERMS coil from stout tanks, normally used to raise mash temps to the desired value. I have used it in a couple ways, including in my molasses settling tank to heat the molasses for the next batch using the PC water during a stripping run.

    In the end, it adds a lot of cleaning that I have found out the hard way, can be done easier by flipping a switch on a pump and a sprayball in a jacket conical fermenter.


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  • @cothermandistillling. I havent used mine to raise temps yet but your right they are a pain to clean. I used to do it manually until I realised you put them in a tank of oxidial and in 12 to 24 hours clean as a whistle. You have be thinking that I should use mine to raise temps when I am doing to runs in a day to preheat a second wash. Thanks mate.

  • @CothermanDistilling nice kit. Just wondering if you could use em for cooling by using em exactly as you would a herms except for cooling instead of heating ie have the coil in an insulated glycol bath & pump the fermenting product through the coil (in the cold bath) when the set temp gets too high?

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